Conveyor belts and conveyor systems are well known systems used for the transport of a variety of materials and products. In underground mining operations, conveyors are used to transport mined materials from the mining machine to their ultimate transportation location.
A variety of different conveying systems and apparatuses have been developed for transferring the mined material from the mining machine to the main belt conveyors. Flexible or articulated mobile conveyor systems are known. Such articulated systems often used in combination with a mining head referred to as a “continuous miner” to enable continuous transport of mined materials produced by the mining head out of the shaft to a collection facility located above-ground. The continuous miner is located at the forward end of a mine shaft, and depending upon the disposition of the mined material within the ground, the shaft often defines a substantially circuitous path through the earth. The great advantage of the flexible conveyor system is that it can conform to this circuitous path to enable the rapid transport of the mined material up and out of the mine shaft without the need for tag-teaming multiple individual straight conveyor systems.
The flexible conveyor system can operate around 60-degree corners, each with a radius of as little as 28 feet, and at speeds of up to 600 feet per minute The system can advance with the continuous miner to allow for up to about 400 feet of continuous mining development, and with any given advance, the continuous miner may accommodate up to four such bends. The conveyor belt used with the flexible conveyor system is thus subjected to extreme in-plane bending when it traverses these bends. A series of closely-spaced hold down edge rollers are employed to extend over the top of the belt to keep the belt troughed and substantially centered as it moves around the bends. Due to the curved path of travel, the edge rollers exert substantial forces on the belt to maintain it in a desired alignment along its path up through the mine workings.
As a result, belts used in these applications typically have very short life spans. One mode of failure is due to edge wear, in which the intense interaction between the idlers and the belt causes wear at the edges to such a degree that the idlers are no longer able to engage or hold down the belt, thus making it impossible to keep the belt troughed or centered. Another failure mode is tearing across the belt width, which can occur at any point on the belt, but which is often experienced adjacent the mechanical splices.
Current belts used with the flexible conveyor system have rubber covers applied over an aramid (i.e., Kevlar) reinforcing layer, with tire cord material embedded in the cover material in the widthwise direction to provide resistance to fastener pullout. Due to the nature of their construction, these belts are handmade.
Thus, there is a need for an improved conveyor belt design for use with a flexible conveyor system. Such an improved belt should have increased resistance to degradation when subjected to extreme in-plane bending conditions to thereby reduce the total system operational costs associated with belt replacement and attendant system shutdown. Such a conveyor belt design should also be amenable to manufacture by modern automated processes to thereby reduce overall manufacturing costs.